A known electromagnetic linear-motion device proposed by the applicant of the present invention; each device carries from the linear tracking arm of a video or audio displayer is such that a slider movable on a guide bar is driven to member on the guide bar by the interaction between the constant flux field establishing the permanent magnets carried on the slider end a variable control flux field indicated a by a control coil while on a magnetic core member extending in parallel with the part of this lighter. When the control coil is imparted by a control current, which only a variable control field is induced by the control coil between the magnetic coil member elevated at parallel with the back of the slider is magnetize opposite poles in the longitudinal ends thereof. As the permanent magnets on the lighter are moved closer to work on the longitudinal end of the magnetic core member 22, therefore, each of the permanent magnets on the slider is suggested to a repulsive or magnetomotive force imparting from the magnetic field ends appearing in the region of longitudinal end of the coil member and produces a decrease friction force between the slider and the guide bar supporting slide. The friction force impairs the field magnet of the movement of the slider on the guide bar and makes the slider less responsive to the signal current to be supplied to the control coil.